Enhanced sensing performance of triboelectric nanosensors by solid-liquid contact electrification

Abstract

Triboelectric nanogenerators (TENGs) and triboelectric nanosensors (TENSs) are the prime backbones for the realization of environmental mechanical energy harvesting and self-powered sensing applications. However, the low efficiency of concurrent solid-solid contact electrification creates a major bottleneck for the growth of highly promising technologies. To address this problem, herein, we report a strategic protocol to design a TENS by solid-liquid contact electrification for chemical sensing purposes as well as an efficient approach for the chemical enhancement of solid-liquid TENGs. In particular, TiO2 nanosheet arrays and various solvents (including water, ethanol and acetone) are employed as solid triboelectric materials and contact liquids, respectively, for the demonstration of solid-liquid contact electrification for mechanical energy harvesting and catechin detection. As a self-powered sensor, the TiO2 nanosheet array-based TENS provides superior advantages such as long-term stability, frequency-independent output and humidity-insensitive properties compared to previously reported solid-solid TENSs. The chemically enhanced sensing mechanism of the TiO2 nanosheet array-based TENS for catechin detection is further confirmed with the decrease in the work function and can provide a wide linear window (100 nM–100 μM) and a low detection limit (30 nM). All the results support that solid-liquid TENSs pave a new path toward efficient self-powered sensors for environmental and healthcare monitoring.